Scientists Say Venus May Have Hosted Life For 3 Billion Years

A study presented by The Goddard Institute for Space Science's Michael Way at the EPSC-DPS Joint Meeting 2019 in Switzerland last Friday indicates that Venus – known for its searing surface temperatures and acidic clouds – may have once been capable of supporting life along with shallow oceans for a period of about three billion years. The findings were derived from a series of five simulations performed by Dr. Way and a colleague, Dr. Anthony D. Del Genio.

In each scenario, all of which assumed varying levels of surface water in the form of oceans and seas, Drs. Way and Del Genio found that Venus would have been able to maintain surface temperatures between 20 and 50 degrees Celsius (68 - 122 degrees Farenheit) for approximately three billion years.

So what changed? One hypothesis is that a planet-wide resurfacing event – perhaps due to volcanic activity – occurred which caused a massive release of carbon dioxide gas stored in Venus' rocks. Such an event would have helped to create the sweltering greenhouse conditions currently found on the planet.

"Something happened on Venus where a huge amount of gas was released into the atmosphere and couldn't be re-absorbed by the rocks," Dr. Way told the Europlanet Society. "On Earth we have some examples of large-scale outgassing, for instance the creation of the Siberian Traps 500 million years ago which is linked to a mass extinction, but nothing on this scale. It completely transformed Venus."

Because Venus has long been thought to be outside the "habitable zone" in its proximity to the Sun, scientists have long theorized that the planet had always been incapable of having liquid water. Dr. Way's findings may lead researchers to rethink the habitability of exoplanets according to the distance of their orbits. In a perfect world, they would also lead humans to consider the implications of letting carbon emissions go unchecked on Earth.

"Our hypothesis is that Venus may have had a stable climate for billions of years," Way explained. "It is possible that the near-global resurfacing event is responsible for its transformation from an Earth-like climate to the hellish hot-house we see today."